For the first time in 83 years, an Old Masters work by Johannes Vermeer is hitting the auction block – but it is so rare, a price can’t be estimated.

Sotheby’s expects to open bidding on the 1670 painting, “Young Woman Seated at the Virginals,” at around $5.4 million at a July 8 sale, but it could zoom to as much as $20 million or higher.

“There hasn’t been a Vermeer sold to the public in more than 80 years, and it’s impossible to determine an accurate estimate,” said a Sotheby’s spokesperson.

The work’s value is also heightened because it was cloaked for a half-century in one of the art world’s most celebrated scandals and mysteries.

In 1947, famed art forger Hans van Meegeren claimed at his trial the work was one of seven fake Vermeers he made from 1937 to 1943. It was purged from the art literature, leaving just 35 authenticated Vermeers in existence.

But in 1960, Belgian collector Baron Frederic Rolin found the disgraced work languishing in an obscure London gallery and snapped it up by swapping it for lesser paintings valued in the thousands.

It took decades, but the work was finally authenticated following a 10-year scientific investigation that ended late last year to put the painting in its place alongside the other 35 life works of Vermeer.

The baron died last year and his heirs are selling the work. The last Vermeer was sold in 1921 in Amsterdam for about $950,000, which in today’s dollars would be about $10 million.